1. Field of the Invention
The present invention relates to a recording liquid container for containing a recording liquid (ink), a recording liquid feed path through which the recording liquid contained in the recording liquid container is conducted to an ink jet head which ejects a recording liquid for adhesion to a recording medium to effect recording, and a recording liquid feed device provided with the recording liquid container and the recording liquid feed path, as well as a hydrophilization method for a surface of a portion of the recording liquid feed device through which portion the recording liquid passes directly and also for the surface of a part of a structure such as a filter which is necessary for the feed of the recording liquid.
The present invention further relates to an element surface modifying method for modifying characteristics and properties of either surfaces of fibers themselves which are used as a negative pressure generating member within the recording liquid container or the said surfaces which have been subjected to a certain treatment, to improve their liquid contact property. The invention still further relates to the so-surface-modified negative pressure generating member.
In addition, the present invention particularly relates to a surface modifying method capable of surely modifying the surfaces of fibers constituted by olefin resins which are difficult to be surface-treated but are environment-friendly, as well as fibers having so-modified surfaces and a method for preparing the fibers.
2. Related Background Art
In an ink jet printer of a type in which a recording liquid (ink) is ejected from an ink jet head and is adhered to a recording medium to effect recording, there generally is provided a recording liquid feed device, which device includes a recording liquid container for containing ink to be fed to an ink jet head and also includes a recording liquid feed path for conducting ink from an ink tank to the ink jet head.
In the case where the recording liquid container and the ink jet head are spaced apart from each other, a flexible plastic tube or the like is used as the recording liquid feed path, and even when there is used a recording liquid container integral with or removable from the ink jet head, there sometimes is used a pipe-like communication member (joint pipe). Usually, a filter is disposed within the path between the head and the tank.
In a recording liquid feed device in which such a feed tube 1001, e.g., a plastic tube, as shown in FIGS. 35A and 35B are used as the aforesaid recording liquid feed path, ink present within the feed tube 1001 evaporates into gas, which gas permeates through the wall of the feed tube 1001 and is discharged to the exterior. It follows that a trace of air enters the feed tube 1001 through the wall of the tube 1001, which entry of air may result in formation of a bubble 1002 within the tube 1001, as shown in FIG. 35A. The bubble 1002 if formed within the feed tube 1001 causes the ink flow path to become narrower, with consequent obstruction to the flow of ink, which may lead to a deficient supply of ink.
Further, if such a state is left as it is over a long period, the bubble will grow into a larger bubble 1002, which may cause separation of the ink present within the feed tube 1001 and formation of meniscuses 1003, as shown in FIG. 35B. Such a state influences the flow of ink and may result in ink being unable to be fed. In this case, even if an attempt is made to recover the continuity of the feed tube 1001, for example by using a pump to suck out the ink from the interior of tube 1001, it may be impossible to recover the tube continuity unless a considerably large force is used.
If a gas barrier layer through which air is difficult to permeate is formed on the wall of the feed tube 1001, the formation of bubbles 1002 may be diminished. With such a gas barrier layer, however, the feed tube 1001 becomes thicker and occupies a larger space. Besides, the feed pipe becomes hard and may be cracked upon imposition of a stress thereon when bent so as to be disposed within the ink jet printer or when the ink jet head moves together with a carriage which carries the ink jet head thereon.
In a recording liquid container having an absorber containing chamber and a liquid storage chamber, the absorber containing chamber having a gas inlet path formed therein for the promotion of gas-liquid exchange, the entry of air into the gas inlet path forms an air path and the entry of the air into liquid storage chamber relieves the internal pressure. In this case, the air moving time dominates an increase in negative pressure during the supply of liquid, so it is preferable that the air move smoothly without the need of increasing a capillary force of the gas inlet path for gas-liquid exchange.
In the case of a recording liquid container in which the liquid storage chamber is replaceable, a joint pipe as an ink flow path, which is relatively long in a lateral direction (horizontal direction), is laid between the liquid storage chamber and the absorber containing chamber, there sometimes occurs a case where the introduction of ink from the liquid storage chamber into the absorber containing chamber is not performed smoothly. Particularly, for example when the ink jet printer is placed obliquely and hence the joint pipe is inclined upward toward the absorber containing chamber, there is a fear that the introduction of ink may not be done smoothly, with consequent exhaustion of ink.
The present invention intends to solve the above-mentioned problems and provide a recording liquid feed path, a recording liquid container, and a recording liquid feed device provided with them, capable of effecting the movement of ink smoothly within a liquid flow path from the recording liquid container to a liquid ejection head/(preferably also within the recording liquid container).
In the case of an ink tank with a compressed member disposed within a liquid feed port of a recording head, the compressed member being constituted by a bundle of fibers which are arranged in alignment with a liquid feed direction, if an ink flow resistance of the compressed member is high and if ink is to be fed at a high flow rate to meet the requirement for high-speed printing, then from the same viewpoint as above, there arises the problem that it is no longer possible to feed ink stably to the head.
The present invention is an epoch-making invention based on a new knowledge found out during our studies about the conventional technical level.
According to the conventional surface modifying method by only a chemical bond based on radical formation, it is impossible to modify a surface of a complicated shape uniformly. Particularly, surface modification is infeasible for the interior of a negative pressure generating member having a complicated porous portion in the interior thereof such as sponge or a fiber composite which is used in the ink jet field for generating a negative pressure.
Besides, if the liquid used contains a surfactant, the porous portion is not surface-modified, and upon extinction of the surfactant the liquid exhibits no characteristic and the characteristic of the surface itself also reverts to its original state immediately.
Olefin resins are superior in water repellence as can be seen from their contact angles as high as 80xc2x0 or more relative to water, but no method is available for ensuring a desired lyophilic nature over a long period.
Having therefore made studies for finding out a method capable of surface-modifying olefin resins in a rational manner and maintaining the thus-modified characteristic and for eventually providing a method capable of surface-modifying all kinds of elements, the present inventors noted the use of a treating liquid and premised that even a negative pressure generating member of a complicated structure could be treated thereby.
Moreover, in connection with the relation between a to-be-modified surface of a negative pressure generating member and a polymer containing a reactive group, we have newly found out that the balance with the reactive group can be controlled to a desired state by utilizing surface energy and that the durability and quality stability can be further improved by analysis of the polymer itself.
Having also paid attention to a negative pressure characteristic of such a negative pressure generating member as a porous member from another viewpoint, we encountered the following problem.
A conventional negative pressure generating member is in many cases exposed to liquid such as a liquid ink filled in an initial stage.
In the case where a negative pressure chamber and a liquid containing chamber are integral with each other, a portion of the negative pressure generating member exposed to the liquid consumes the liquid, which consumed quantity of the liquid may be replenished. However, the interior of the device concerned, which is in a normal condition, does not assume that the liquid will be replenished to the negative pressure generating member which consumes the liquid as a whole. Thus, it is uncertain even for those skilled in the art whether a return to the initial negative pressure or to the initial liquid retention will be attained or not by the replenishment of liquid.
Having made a further study about what degree of return will be attained by mounting a replenishing liquid containing chamber (a container or a tank) after the liquid contained in a negative pressure generating member containing chamber has been consumed at an arbitrary level, we found out that the amount of the liquid filled into the negative pressure generating member in an initial stage was fairly large because of forced pouring of the liquid by some suitable means, but that a mere re-filling of the liquid afforded only about a half return probably due to a difficult removal of air contained in the negative pressure generating member, and that if such a mere replenishment of liquid is repeated, the amount of liquid capable of being retained would become more and more smaller and an increase in negative pressure also resulted.
It is a first object of the present invention to provide a liquid feed path in which even when a bubble is present in a liquid feed tube portion leading to a liquid ejection head, the path can be recovered by suction or the application of pressure using recovery means.
It is a second object of the present invention to provide a liquid feed path having a lyophilized surface formed on an inner surface thereof, the lyophilized surface being formed using a thin polymer film of a molecular level which causes little change in the inside diameter of the path and the manufacturing method therefor.
It is a third object of the present invention to provide a containing chamber capable of containing liquid to be fed to a liquid ejection head and improved in liquid movability and recoverability in a joint potion (connector portion) of a negative pressure generating member containing chamber to and from which a removable liquid feed member is connected and removed, and also provide a containing chamber involving a lyophilization treatment for at least a part of a negative pressure generating member. It is also an object of the invention to provide a containing chamber and a system both capable of ensuring the introduction of gas (outside air) which is performed together with the supply of liquid into a negative pressure generating chamber by the liquid feed member.
It is a fourth object of the present invention to provide a liquid feed tube manufacturing method for ensuring a lyophilic nature of an inner surface of an olefin resin tube for a liquid ejection head, as well as a liquid feed tube manufactured by the method.
It is a fifth object of the present invention to provide structural members such as a tube, a pipe, and a filter capable of exhibiting a lyophilic nature and also exhibiting air permeability and elution preventing effect in a liquid feed path formed within a liquid ejection device.
Other objects of the present invention and combined objects of the above objects will be understood from the following description.
For achieving the above-mentioned objects, according to the present invention there is provided a tubular recording liquid feed path as path portion through which a recording liquid passes directly or as a structure necessary for the feed of the recording liquid, to feed the recording liquid to an ink jet head which ejects the recording liquid to effect recording,
in which a polymer is applied to an inner surface of the recording liquid feed path, the polymer having a first moiety containing a lyophilic group for making the inner surface of the recording liquid feed path hydrophilic and a second moiety containing a group having an interfacial energy different from an interfacial energy of the lyophilic group and almost equal to a surface energy of the said surface, the second moiety being oriented toward the said surface which direction is different from an orienting direction of the first moiety.
According to this construction, when air permeates through the wall of the recording liquid feed path and forms a bubble in the interior of the same path, the recording liquid is conducted along the hydrophilized inner surface of the recording liquid feed path in the wall portion of the same path with the bubble adhered thereto, so that the area of bubble adhesion to the inner surface of the path becomes small; besides, the bubble leaves the inner surface of the path and floats. Consequently, the bubble can be removed easily by the flow of liquid during feed of the liquid and thus the stay of the bubble within the path can be shortened. Consequently, the flow of the recording liquid can be prevented from being obstructed by the bubble and the recording liquid can be fed efficiently.
If a bubble adheres to the inner surface of the recording liquid feed path, the osmotic pressure of the recording liquid in this bubble-adhered portion of the path becomes smaller, thus promoting the permeation of air into the same path. However, in the recording liquid feed path according to the present invention, since the area of bubble adhesion to the inner surface of the recording liquid feed path can be made small, the permeation of air into the recording liquid feed path, which is caused by a lowering of the osmotic pressure of the recording liquid, can be prevented from being accelerated.
Since the hydrophilized inner surface of the recording liquid feed path according to the present invention is low in flow resistance during movement of the recording liquid, the recording liquid can be fed more efficiently through the recording liquid feed path.
For effecting this hydrophilization, the inner surface of the recording liquid feed path may be constituted by an olefin resin, and a polyalkylsiloxane containing a hydrophilic group may be used as a polymer.
According to the present invention there is further provided a recording liquid feed system comprising a first container, the first container containing an absorber which holds a recording liquid to be fed to an ink jet head temporarily with a capillary force, a second container which holds a recording liquid to be fed to the first container, and a tubular recording liquid feed path for communication between the first and second containers,
in which the absorber is a fibrous member constituted by fibers which contain an olefin resin at least on their surfaces, an inner surface of the recording liquid feed path has an olefin resin, the surface of the fibrous member and the inner surface of the recording liquid feed path are each applied with a polymer at least partially, the polymer having a first moiety containing a lyophilic group for lyophilization and a second moiety containing a group having an interfacial energy different from an interfacial energy of the lyophilic group and almost equal to a surface energy of the said surfaces, the second moiety being oriented toward the said surfaces, and the first moiety being oriented in a direction different from the said surfaces.
According to this construction, since the surface of the fibrous member contained in the absorber is hydrophilized, the surfaces of the constituent fibers are high in wettability, so that the absorption of ink by the fibrous absorber is fast and there can be attained an efficient feed of ink to the absorber. Besides, since the flow resistance during movement of the ink is low in the fibrous absorber portion, it is possible to conduct the ink to the ink jet head efficiently.
According to the present invention there is further provided a recording liquid container containing a recording liquid to be fed to an ink jet head which ejects a recording ink for adhesion to a recording medium to effect recording,
in which a partial surface of a portion through which the recording liquid passes directly or a partial surface of a structure necessary for feeding the recording liquid is hydrophilized.
According to this construction, there can be obtained a recording liquid container capable of feeding a recording liquid stably and efficiently.
More specifically, according to the present invention there is provided a recording liquid container including a filter disposed in a feed port portion for the feed of a recording liquid to an ink jet head,
in which the surface of the filter is hydrophilized.
By so making the filter hydrophilic it is possible to diminish a pressure loss caused by the filter and conduct a recording liquid held in an ink cartridge to the filter portion efficiently and feed it to the exterior.
According to the present invention there is further provided a recording liquid container comprising an absorber containing chamber and a liquid storage chamber, the absorber containing chamber containing an absorber and being provided with an atmosphere communication port and a liquid feed port, the absorber functioning to hold liquid by utilizing a capillary force, and the liquid storage chamber communicating with the absorber containing chamber through a communicating portion and defining a substantially sealed space except the communicating portion,
in which a housing of the absorber containing chamber is lyophilized at a surface of contact thereof with the absorber at least in the vicinity of the communicating portion.
According to this construction, at the surface of contact with the absorber on the side where the communicating portion is connected to the absorber containing chamber, even if there is a slight gap between the absorber containing chamber and the absorber, the recording liquid held by the absorber can be conducted to the said gap and held therein, whereby it is possible to prevent air from being conducted through the gap to the communicating portion and hence possible to effect gas-liquid exchange stably.
According to the present invention there is further provided a recording liquid container containing an absorber and provided with an atmosphere communication port and a liquid feed port, the absorber functioning to hold a recording liquid by utilizing a capillary force, and further provided with a joint pipe for introducing the recording liquid into the absorber,
in which an inner surface of the joint pipe is lyophilized.
By thus making the inner surface of the joint pipe hydrophilic it is possible to conduct the recording liquid stored in the liquid storage chamber to the joint pipe portion efficiently and feed it into the absorber containing chamber.
In this case, by making the inner surface of a lower portion of the joint pipe hydrophilic, thereby allowing ink to pass through a lower portion of the pipe and allowing air to pass through an upper portion of the pipe, it is possible to effect gas-liquid exchange in a more stable manner.
Further, if an inner surface of a connection port of the liquid storage chamber for connection with the joint pipe is made liquid-repellent, it becomes possible to prevent the recording liquid from staying in the connection port of the liquid storage chamber when the same chamber is removed from the absorber containing chamber.
It is preferable that the absorber be constituted by a fibrous member and that both a portion of the fibrous member corresponding to the liquid feed port and a surrounding portion thereof be subjected to a lyophilizing treatment at least partially. By so doing it is possible to improve the recording liquid absorbability of the absorber and decrease the flow resistance of the recording liquid contained in the absorber.
The lyophilizing treatment according to the present invention for a partial surface of a portion of the recording liquid container through which the recording liquid passes directly or for the surface of a part of a structure necessary for the feed of the recording liquid is characterized in that a polymer is applied to the surface to be rendered lyophilic, the polymer having a first moiety containing a lyophilic group for making the surface lyophilic and a second moiety containing a group having an interfacial energy different from an interfacial energy of the lyophilic group and almost equal to a surface energy of the said surface, the second moiety being oriented toward the said surface, and the first moiety being oriented in a direction different from the said surface.
According to the present invention there is further provided a recording liquid feed device for feeding a recording liquid to an ink jet head which ejects the recording liquid for adhesion to a recording medium to effect recording,
in which a polymer is applied to a partial surface of a path portion through which the recording liquid passes directly and is applied also to a partial surface of a part of a negative pressure generating member which feeds the recording liquid while generating a negative pressure, the polymer having a first moiety containing a lyophilic group for making the said surfaces lyophilic and a second moiety containing a group having an interfacial energy different from an interfacial energy of the lyophilic group and almost equal to a surface energy of the said surfaces, the second moiety being oriented toward the said surfaces, and the first moiety being oriented in a different direction.
More specifically, the recording liquid feed device according to the present invention is characterized by having the foregoing recording liquid feed path or recording liquid container.
According to the present invention there is further provided a surface modifying method for lyophilizing or liquid-repelizing a partial surface of a path portion through which a recording liquid passes directly in a recording liquid feed device for feeding the recording liquid to a liquid ejection head or a partial surface which constitutes a part of a filter necessary for feeding the recording liquid, with a functional group for the lyophilization or liquid-repellant treatment being imparted to the partial surface, the method comprising:
a first step of applying liquid containing fragmented products to the partial surface, the fragmented products having a first moiety containing a functional group and a second moiety containing a group having an interfacial energy different from an interfacial energy of the functional group and almost equal to a surface energy of the partial surface, the fragmented products being obtained by cleavage of a functional group imparting polymer having the first and second moieties;
a second step of orienting the second moiety of the fragmented products to the partial surface side and orienting the first moiety to a side different from the partial surface side; and
a third step of condensing and polymerizing at least partially the fragmented products oriented on the partial surface.
Further, a surface modifying method according to the present invention is characterized by comprising:
a first step of applying a solution to a surface in which solution are dissolved a dilute acid, an affinity improver for improving volatility and affinity for an element surface, and a treating agent containing a polymer, the polymer having a second moiety and a first moiety, the second moiety containing a group having an interfacial energy almost equal to a surface energy of the surface, and the first moiety containing a group of an interfacial energy different from the said interfacial energy;
a second step of imparting heat to the surface to remove the affinity improving agent;
a third step of concentrating the dilute acid and allowing the polymer contained in the treating agent to be cleaved; and
a fourth step of condensing the cleaved polymer on the surface, orienting the second moiety of the polymer toward the said surface, and orienting the first moiety to a side different from the said surface.
According to this surface modifying method it is possible to conduct a uniform and continuous surface modifying treatment. By so modifying the surface it is possible to improve the fluidity of a recording liquid which comes into contact with the surface.
Thus, according to the present invention, the wettability of ink for the liquid feed path as a path portion through which the recording liquid passes directly or as a structure necessary for the feed of the liquid is improved, the adhesion of a bubble becomes difficult, a bubble even if formed is difficult to grow even when left standing over a long period, the adhesion and staying of a bubble within the liquid feed path are suppressed, and the ink feedability is difficult to be deteriorated.
Further, by applying the hydrophilizing treatment to a partition wall on a absorber containing chamber side in a liquid container having the partition wall, it is possible to prevent an accidental occurrence of an air path between the wall surface and the absorber and it is possible to effect the introduction of gas through a predetermined route, thus permitting gas-liquid exchange to be carried out stably and permitting improvement of the reliability in the feed of liquid.